Millions of people around the world suffer from conditions caused by hormone disorders, including diabetes, pituitary dwarfism and other hypopituitarisms, pituitary gigantism and other hyperpituitarisms, galactorrhea, hypothyroidism (myxedema) and hyperthyroidisms, adrenocortical insufficiencies (e.g., Addison's disease) or hyperfunctions (e.g., Cushing's syndrome), pheochromocytoma, multiple endocrine neoplasias, polyglandular deficiency syndromes, and disorders of reproductive function.
Diabetes mellitus is a hormone disorder which afflicts millions of people annually. It is a serious and important health problem, involving 2 per cent or more of the US population. It is characterized by an inability to maintain homeostasis of glucose in the bloodstream. Thus the primary symptom of acute diabetes is hyperglycemia. A secondary set of symptoms arises in chronic or long-standing diabetes. These include degeneration of the walls of blood vessels, causing serious vascular complications involving both macro- and microvessels. Many different organs are affected by these complications, and common late clinical manifestations are retinopathy (chronic diabetes is a leading cause of blindness), nephropathy, neuropathy and foot ulcers.
In normal individuals, an increase in glucose concentration in the blood ("blood glucose") triggers the release of insulin from the pancreas into the bloodstream. This in turn leads to uptake of glucose into tissues and its conversion into glycogen and fatty acids. In most diabetic individuals there is a deficiency in the production, release, stability or uptake of insulin. This results in an inability to remove glucose from the bloodstream and to store its fuel content by metabolizing it into glycogen and fatty acids. Even in the presence of elevated blood glucose, the metabolism of a diabetic is geared towards the synthesis of glucose via gluconeogenesis and the oxidative breakdown of fatty acids.
Many other hormone disorders are characterized by an under- or over-abundance of the hormone in question, due to abnormalities in its synthesis, release or rate of elimination from the bloodstream, and/or by the inability of target cells to respond normally to the hormone, due to abnormalities in the number or function of receptors for the hormone or in the signal transduction pathways which mediate cells' responses to the hormone.